Yes, the term "optimisers" is not exactly accurate. They renamed them because many newer model bikes don't fall for the resistor-in-the-heater-circuit trick. So, Dynojet have two products - one is the resistor, and the other is an actual optimiser but they call them both the same thing.
What the real optimisers do is take the O2 sensor signal and mess with it, so that when the bike's ECU thinks it's hitting 14.7 AFR it's actually hitting about 13.6 AFR. I believe they're simple voltage dividers which convert a signal of 0.75 volts from the O2 sensor into about 0.500 volts (which denotes 14.7 AFR). So the bike ECU sees 0.5 volts but in order to see that number it actually has to richen up the mixture so that it's *actually* creating a 0.75 volt reading from the O2 sensor. They do not offer this product for the VFR800 because the ECU in our bikes is so brain-dead it's easy to fool. In fact I think all the Honda systems are still dumb as dog crap. If you go to the Powercommander website, install instructions for Honda bikes will say "plug in O2 optimiser, you can then leave the O2 sensor disconnected or remove it from the exhaust". However for a modern Yamaha bike, the install instructions will say "plug the optimiser in-line between the O2 sensor and the ECU". Subtle difference, no?
For those bikes, the Powercommander instructions will also say stuff like "don't tune any cells between 0 and 15 percent throttle and 0-6,000rpm". However, since the Honda is, as I say, brain-dead you are actually able to tune the Powercommander in those ranges. So I guess the Honda stupidity kind of makes it easier to tweak the bike...
There are more advanced systems on the market (not from Dynojet) which replace the narrowband O2 sensor with a wideband one, but include a calculated narrowband voltage output. These are nifty for engine tuning whilst keeping the closed loop capabilities of the stock ECU in place.
Does that make sense?